This invention relates generally to returned stair treads and more specifically to wooden returned stair treads containing exposed joints on forward end portions thereof that will not pull apart, gap or otherwise become deformed due to changes in ambient temperature and humidity or changes in the moisture content of the wood.
Returned stair treads, generally speaking, have long been known and used in the prior art. Typically, such prior art stair treads include a tread constructed of wood with a return nosing affixed to a side edge of the former so as to form an exposed joint along a forward edge portion of the assembly. Such prior art nosings are usually glued to the side of the stair treads along the entire length thereof and, in addition, are nailed to their respective treads at several different positions therealong.
A major problem that has been encountered with such prior art construction is that the exposed joint tends to open or become gapped or otherwise deformed in an unsightly manner when the returned stair tread is exposed to ambient temperature and humidity conditions beyond those encountered when the nosing was originally affixed to the stair tread. Such conditions are usually at their worst during late Summer when returned treads are stored or otherwise disposed in non-air conditioned surroundings such as a warehouse or building under construction.
I have previously developed a returned stair tread having a moisture compensated joint which overcomes these prior art difficulties. See my U.S. Pat. No. 4,730,425 issued Mar. 15, 1988. That patent discloses both a shaped joint and mitered joint for a returned stair tread wherein, in one embodiment, only the forward region of the joint itself is glued, the remainder of the nosing being slidable along the side of its corresponding stair tread due to tongue and groove connection between them. In the alternative, my said patent teaches that the nosing may be secured to the side of the tread by means of a single nail or other suitable mechanical fastener driven through the nosing and into the tread at or very near the rear end of the shaped or mitered joint, while the remainder of the nosing is slidable along the tread due to tongue and groove connection between them. Also my said patent teaches that the shaped or mitered joint may be secured by both glue applied between the nosing and tread in the region of the joint and also nailed or otherwise mechanically fastened with a single nail or fastener as previously described, with the remaining portion of the nosing and tread being slidable relative to one another by means of tongue and groove construction therebetween.
Since the issuance of that patent, I have discovered two additional forms of moisture compensated construction for returned stair treads which will likewise substantially reduce or eliminate unsightly gapping of a shaped or mitered joint on the forward end portion of the nosing and tread. These additional types of construction now permit a range of choices in overcoming the unsightly gapping problem of the exposed joint that has been encountered in returned stair treads of the prior art due to variations in temperature and humidity and in the moisture content of the wooden tread. Moreover, these new types of construction eliminate the need for tongue and groove interconnection between the nosing and tread.